Students are finding the combination locks in school hard to use. The students are trying to find a solution that does not cost too much and that they can do right away. Which solution should they choose?

• Buy bigger and better locks online.

• Give students a list of other locks to buy.

• Have students practice using the locks in class.

• Find old locks from other schools that are easier to use.

Joel designed a tool for picking up metal screws that fall while he works on his car. The tool picks up the screws but drops them before Joel can pull them out. Which design change should he try next?

• Make the tool heavier.

• Make the handle longer.

• Use a different type of screw on his car.

• Attach a strong magnet to the end of the tool.

Paul and Kat work together to test different kinds of popcorn salt to see which one people like the most. Which step should they take to make sure their tests are fair?

• Have one person try each batch.

• Cook each test batch in a different microwave.

• Put the same amount of salt on each test batch.

• Use different kinds of popcorn for each test batch.

Jane and Todd are making a weathervane that tells the direction of the wind. They tested three prototype designs in the same location. They recorded the direction each one was pointing in. They did this every hour for four hours. Jane and Todd compared their data to the data of a local weather station. Which question were they trying to answer?

• Which prototype is the easiest to use in the wind?

• Which prototype gives the most accurate direction?

• Which prototype moves the fastest in one direction?

• Which prototype is more resistant to extreme weather?

Farmers want to improve their farms with better technology. Which methods will help them meet this need?

• Use GPS for field mapping.

• Rent old tractors to plow fields.

• Invest in modern milking machines.

• Hire more workers to harvest the crops.

• Use computers to control farm equipment.

Jim's friend suggests he use a piece of two-dollar plastic as part of a roof design for the bird feeder. This material would last longer because it would not rot. Which requirements would this suggestion fall under?

• Protect the seeds and cost less.

• Make room for more seeds and birds.

• Make more room for birds and cost less.

• Protect the birds from predators and heat.

The two designs Jim selected need to be tested. Which test should Jim use?

• Place each feeder in a different backyard.

• Place one feeder on the ground and hang the other in a tree.

• Hang both feeders at the same height on one tree in his backyard.

• Hang one feeder in one tree and the other in another tree in his backyard.

John is designing a windmill for his science project. He is considering using a lightweight metal for the blades of the windmill. This would allow the blades to spin faster in the wind. Which requirements would this decision meet?

• Make the windmill more durable and cost-effective.

• Improve the windmill's efficiency and reduce its weight.

• Make the windmill more attractive and unique.

• Improve the windmill's stability and resistance to wind.

Sam is testing different types of paper to see which one can hold the most water. What should he do to ensure his test is fair?

• Use different sizes of paper for each test.

• Use the same amount of water for each test.

• Test each paper in a different room.

• Use different types of water for each test.

Lisa designed a device for picking up fallen leaves in her garden. The device picks up the leaves but can't hold them for long. What design change should she consider?

• Make the device lighter.

• Attach a larger bag to the device.

• Use a different type of leaf in her garden.

• Make the handle of the device shorter.